Bay quality suffering, report says
"The conditions of the north part of the bay are alarming," said Grant Davis, executive director of The Bay Institute, a Novato-based bay advocacy and education group. While plankton, shellfish and fish populations generally increased or held steady in the Central and South Bay areas, according to the report, population levels of the same organisms are low in the upper bay - the body of water east of Marin. It was the second report examining the entire estuary from the North to South bays and follows a study done in 2003. In Suisun Bay to the east, not only fish, but phytoplankton counts are down significantly compared with numbers taken 20 years ago. Because sea life typically collapses from the top down, there is concern that phytoplankton in San Pablo Bay could follow the downfall of its fish populations, scientists say. Since the early 1980s, the open water fish population is down 69 percent in San Pablo Bay . Phytoplankton and zooplankton - microscopic plants and animals - are the foundation of the aquatic food web. The lack of freshwater flow from the Sierra, through the Delta and into the bay is part of the problem, scientists say. The flow transports nutrients into the bay. "The bay suffers from chronic drought because so much water is diverted from its watershed," said Tina Swanson, a fish biologist at the institute who helped prepare the report. "And because many of the bay's native fish and wildlife depend on those freshwater flows, those species are not recovering from the deep decline they experienced over the last several decades." Farming operations in the Central Valley , the construction of reservoirs and canals, and the exporting of water from rivers and the Delta have reduced the flow of freshwater to the bay, resulting in more brine, according to the report. "Those issues have to be addressed or the estuary is in trouble," she said. "The index shows that the further up the bay, the worse the condition." San Pablo Bay is one of the most polluted in the estuary, according to the study. "There is a lot of industry along the bay," Swanson said. The San Francisco Bay is the largest estuary - where the ocean and freshwater meet - on the West Coast and provides habitat for hundreds of plants and animal species unique to the region. The report did show moderate improvement in some important areas including shellfish populations, reflecting rising shrimp and crab numbers in the Central and South bays. Other indicators suggest that efforts to reduce water pollution and restore habitat in San Francisco Bay seem to be working. "Improving grades are an encouraging sign that stewardship efforts around the bay are making a difference," Davis said. "At the same time, the index results are a critical reminder that the bay does not exist in a vacuum and that its health is directly impacted by events upstream." http://www.marinij.com/searchresults/ci_3075122
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